The area from Cape Cod to Nova Scotia is the Gulf of Maine: 70,000 square miles of life as deep as the Empire State Building and as cold as the refrigerator in your kitchen. If someone asks where I’m from, I say “Maine,” but I’d probably do better to say “the Gulf of Maine.” That second answer would emphasize coastline and islands quilted with spruce and known to heron and osprey. The prevailing winds blow from southwest to northeast, from Cape Cod’s glossy tip to the matte-gray breakers off Cape Sable, a journey of 300 miles, if run by sailboats in the Marblehead to Halifax Ocean Race. It’s no surprise these racers encounter a living ocean’s emissaries in that rich expanse of currents and banks. Out there are fin whales, right whales, humpbacks and sharks. Maybe you’ve been, and out there you saw terns, gannets, gulls and storm petrels. Of course, amid these visitors to the surface are hints of deeper play from mackerel, herring, haddock and hake.